There was a lot of excitement in Mt. Saint Helens, Washington. Geologists were monitoring the Mount Saint Helens volcano. Seismicity began several days before March 20, 1980, when an earthquake of 4.2 centered under the volcano commanded wide attention. The first of a series of small phreatic explosions occurred on March 27, accompanying the opening of a crater northward at the summit of the cone. Strong seismicity continued, at times bursts of deep volcanic tremor was felt statewide in …showed first 75 words of 822 total…

…showed last 75 words of 822 total…American Geophysical Union Field Trip Guidebook T106 9 Http://volcano.und.nodak.edu/vwdocs/frequent_questions/group6_new.html Scott Rowland, University of Hawaii, Steve Mattox, University of North Dakota, John Dvorak 10 Volcanoes of the World, by Tom Simkin and Lee Seibert 11 "Eruption of Mt. St. Helens, 5/18/1980." Http://www.smate.wwu.edu/teched/geology/vo-St-Helens.html Accessed 10/12/2003. 12 http://www.smate.wwu.edu/teched/geology/vo-St-Helens.html Accessed 10/12/2003. 13 http://www.olywa.net/radu/valerie/StHelens.html Accessed 10/2/2003.